# sumup-debug

> Claude/Codex skill by [@sumup](https://omgskills.com/library/sumup/index.md) · 5 stars · Updated 2026-10-17

Troubleshoot common SumUp integration failures. Use when SumUp HMAC signature checks fail, checkout sessions expire, scopes aren't activated, widget mount is blocked, affiliate keys don't match, or \`checkout\_reference\` collides.

Tags: agent-skills, ai, gemini-cli-extension, payments, sumup

## Install

```sh
git clone https://github.com/sumup/sumup-skills /tmp/sumup-skills && ln -s /tmp/sumup-skills/skills/sumup-debug ~/.claude/skills/sumup-debug
```

## From README

SumUp Troubleshooting Playbook Use this skill for diagnosis and remediation of failing SumUp integrations. Fast Triage Matrix Classify symptom: Auth/signature error Checkout creation/processing error Widget/client-side mount or flow error Async mismatch (success in UI, failure in backend state) Capture evidence: request/response payloads (sanitized), HTTP status, error code/message checkout id, merchant code, checkoutreference webhook delivery id and signature verdict Reproduce in sandbox before changing production behavior. Common Failures and Fixes HMAC signature mismatch (x-payload-signature) Symptoms: Webhook verification fails for all events or intermittently. Likely causes: Body parser mutates payload before verification. Wrong webhook secret/environment pair. Digest computed with non-raw body bytes. Fix: Verify against raw request body bytes. Ensure HMAC SHA-256 with exact configured secret. Confirm secret belongs to the same merchant/environment.

## Links

- HTML page: https://omgskills.com/library/sumup/sumup-skills/skills/sumup-debug/
- GitHub: https://github.com/sumup/sumup-skills
- Author: [@sumup](https://omgskills.com/library/sumup/index.md)

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